build-sys: include tests in installation

This also allows tests to be run against he build directory:
$ py.test-2.7 -v build/lib.linux-x86_64-2.7 docs
$ py.test-3.4 -v build/lib.linux-x86_64-3.4 docs

Author: keszybz

setup.py

@@ -95,7 +95,8 @@ def lib(*names, **kw):
            'Topic :: System :: Logging',
            'License :: OSI Approved :: GNU Lesser General Public License v2 or later (LGPLv2+)',
            ],
-       py_modules = ['systemd.journal', 'systemd.daemon'],
+       py_modules = ['systemd.journal', 'systemd.daemon',
+                     'systemd.test.test_daemon', 'systemd.test.test_journal'],
        ext_modules = [_journal,
                       _reader,
                       _daemon,